Method for efficient resource utilization of iron-containing dust sludge

Abstract

The application discloses a kind of high-efficiency resourceization comprehensive utilization method of iron-containing dust sludge, comprising the following steps: (1) iron-containing dust sludge is stirred and pulped, and is treated by screening and residue separation, to obtain undersize material slurry;(2) undersize material slurry is subjected to flotation-weak magnetic-strong magnetic process or weak magnetic-strong magnetic process.The application can separate iron, carbon, zinc and potassium in iron-containing dust sludge at one time, without waste residue and wastewater discharge, and belongs to an environmentally friendly process.In the process technology route, efficient flotation, weak magnetic-strong magnetic separation technology is combined with mature potassium chloride crystallization process and mature zinc extraction technology, so that each component of iron-containing dust sludge is efficiently recycled and utilized.The process route of the application is simple, concise, efficient and reasonable, can be adapted to treat various iron-containing dust sludge, has strong overall adaptability, good economic benefits and high social benefits.

Description

Technical Field

[0001] This invention belongs to the field of solid waste disposal technology, and in particular relates to a method for the efficient and comprehensive utilization of iron-containing dust and sludge. Background Technology

[0002] Iron-containing dust and sludge is a collective term for dust generated during various processes in steel smelting and rolling, as well as sludge from wastewater treatment. It is the most diverse and complex type of waste in the steel production process, with dust being the main component. Due to the presence of harmful elements such as potassium, sodium, zinc, and sulfur, iron-containing dust and sludge cannot be directly returned to the smelting system.

[0003] Overseas, pyrometallurgical processes are commonly used to treat iron-containing dust and sludge, but these involve large investments and high costs, making them unaffordable for domestic enterprises. Domestic steel companies exhibit significant differences in the particle size and composition of iron-containing dust and sludge due to variations in raw materials and dust collection processes. Few companies engage in large-scale treatment of iron-containing dust and sludge, and the technical specifications vary considerably due to the differences in the properties of the dust and sludge. Most methods of disposing of iron-containing dust and sludge involve stockpiling, partial recycling within the smelting system (affecting process parameters), or sale as feedstock. The few treatment processes available generally only target iron, resulting in low comprehensive utilization rates and persistent environmental pollution problems.

[0004] Patent CN 110586318 A relates to a method for the comprehensive utilization of blast furnace ash, employing flotation-cyclone classification-weak magnetic separation-strong magnetic separation to comprehensively recover coke powder and magnetic minerals from blast furnace ash. This method only addresses blast furnace ash and does not mention treatment methods for other iron-containing dust and sludge from the steel production process, lacking adaptability. Furthermore, the use of cyclone classification for particle size separation makes precise classification control difficult. Patent CN 110369119 B relates to a comprehensive recovery process for iron, carbon, and zinc from steel plant dust waste, employing pre-precision classification-strong magnetic separation-gravity separation to comprehensively recover valuable elements such as iron, carbon, and zinc from steel plant dust, producing iron concentrate, carbon concentrate, and zinc concentrate. This method requires highly precise classification in practice, and the use of gravity separation results in low single-unit processing capacity and low separation accuracy.

[0005] In order to achieve the sustainable and healthy development of my country's steel industry, effectively improve resource utilization efficiency, and reduce or eliminate environmental pollution, it is of great significance to conduct research on efficient resource utilization technologies for iron-containing dust and sludge generated during steel production. This research can not only systematically solve the problem of comprehensive utilization of iron-containing dust and sludge and provide support for the sustainable development of my country's steel enterprises, but also effectively reduce the pollution caused by iron-containing dust and sludge during transportation and storage. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above and to provide a method for the efficient and comprehensive utilization of iron-containing dust and sludge.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0008] A method for the efficient and comprehensive utilization of iron-containing dust and sludge includes the following steps:

[0009] (1) The iron-containing dust and mud are stirred, pulped, and screened to separate the slag, resulting in undersize slurry.

[0010] (2) The screened slurry is subjected to flotation-weak magnetic-strong magnetic process or weak magnetic-strong magnetic process.

[0011] In the above-described method of this invention, the undersize slurry after screening and slag separation is directly fed into the beneficiation process in its entirety, without the need for classification equipment such as spiral centrifugal classifiers or hydrocyclones to classify the material before feeding it into the beneficiation process. This simplifies the process flow and enhances its adaptability to different materials. Furthermore, the undersize slurry only requires treatment using either a "flotation-weak magnetic-strong magnetic process" or a "weak magnetic-strong magnetic process," eliminating the need for gravity separation equipment such as vibrating cone concentrators. This further simplifies the process flow. Compared to gravity separation, flotation and magnetic separation equipment have a higher single-unit processing capacity.

[0012] Preferably, the iron-containing dust is one or more of blast furnace dust, machine head dust, and cyclone dust; the blast furnace dust has a carbon content of <30%, an iron content of <50%, and a zinc content of <8%; the machine head dust has a carbon content of <5%, an iron content of <30%, and a zinc content of <1%; and the cyclone dust has a carbon content of <30%, an iron content of <50%, and a zinc content of <1%.

[0013] Preferably, when the iron-containing dust is blast furnace dust, the undersize slurry is subjected to a flotation-weak magnetic-strong magnetic process; when the iron-containing dust is one or more of machine head ash and cyclone ash, the undersize slurry is subjected to a weak magnetic-strong magnetic process. Alternatively, machine head ash and cyclone ash can also be treated using a flotation-weak magnetic-strong magnetic process; the only requirement is to adjust the dosage of collector and frother to the minimum, or even omit them altogether.

[0014] Preferably, the stirring and pulping, and screening and slag removal process includes the following steps: the pulping process involves stirring and pulping iron-containing dust and sludge to prepare a slurry with a mass concentration of 20-30%; the screening and slag removal process uses a high-frequency fine screen or a linear vibrating screen with a screen aperture size of 0.3-0.6 mm, and the screening and slag removal process yields undersize slurry with a mass concentration of 15-25%.

[0015] Preferably, the flotation-weak magnetic field-strong magnetic field process includes the following steps:

[0016] ① The undersize slurry obtained from step (1) is subjected to roughing flotation 1 to 3 times, and the froth products obtained from the roughing flotation are combined into carbon crude concentrate products;

[0017] ②The carbon rough concentrate product obtained in step ① is subjected to 1 to 3 more fine flotation operations to obtain the final fine froth product, which is the carbon concentrate product; the fine flotation operation can be a blank fine flotation operation;

[0018] ③ The products obtained from the roughing flotation operations in step ① are subjected to 1 to 2 weak magnetic separations and 1 to 2 strong magnetic separations respectively. The weak magnetic concentrate and strong magnetic concentrate are then combined to form iron concentrate products.

[0019] ④ Combine the tailings obtained from the strong magnetic separation in step ③ and the in-tank product obtained from the fine flotation operation in step ② into a zinc-containing product.

[0020] The flotation-weak magnetic field-strong magnetic field process of this invention is simple, adaptable, and highly effective.

[0021] Preferably, in steps ① and ②, the flotation equipment used is a flotation machine or a flotation column; in the first to third roughing flotation operations of step ①, the flotation collector used is at least one of diesel oil and kerosene, the frother used is MIBC (methyl isobutyl methanol), the total amount of flotation collector added is 500-1000 g / t of raw material, the ratio of flotation collector to frother added is 2.5:1-5:1, and the flotation aeration rate is 0.2-0.4 m³ / t. 3 .m -2 .min -1 The flotation frother used is MIBC, which features brittle flotation foam with low viscosity, reducing entrainment during flotation and improving the quality of the foam product. Further preferably, the flotation equipment used is a flotation column, which has advantages such as large single-unit processing capacity and high separation efficiency.

[0022] Preferably, the weak magnetic field-strong magnetic field process includes the following steps:

[0023] ①The undersize slurry obtained from step (1) is subjected to 1-2 weak magnetic separations and 1-2 strong magnetic separations. The resulting weak magnetic concentrate and strong magnetic concentrate are combined to form an iron concentrate product.

[0024] ② For the strong magnetic separation tailings obtained in step ①, when the carbon content of the strong magnetic separation tailings is >55%, the strong magnetic separation tailings are directly used as carbon concentrate products without flotation processing; when the carbon content of the strong magnetic separation tailings is >15% and ≤55%, it cannot be directly used as carbon concentrate products, and the undersize slurry obtained in step (1) is processed by the flotation-weak magnetic-strong magnetic process; when the carbon content of the strong magnetic separation tailings is ≤15%, the strong magnetic separation tailings are used as raw materials for making building materials.

[0025] The weak magnetic-strong magnetic separation process is actually configured according to the flotation-weak magnetic-strong magnetic separation principle to improve its adaptability to different iron-containing dust and sludge. In the weak magnetic-strong magnetic separation process, the tailings obtained in step ② are mostly used as raw materials for making building materials, especially when the carbon content of the tailings is <15%.

[0026] In the above-mentioned weak magnetic field-strong magnetic field process and flotation-weak magnetic field-strong magnetic field principle process:

[0027] Preferably, the iron content of the iron concentrate product is greater than 50%, and the carbon content of the carbon concentrate product is greater than 55%.

[0028] Preferably, the weak magnetic separation operation uses an electromagnetic or permanent magnet weak magnetic separator, and the strong magnetic separation operation uses a ZH-type flat ring strong magnetic separator or a Slon vertical ring strong magnetic separator; the weak magnetic separation is carried out at a magnetic induction intensity of 0.15 to 0.22 T, mainly used to recover iron-containing minerals such as magnetite with strong magnetic separation, and the strong magnetic separation is carried out at a magnetic induction intensity of 0.6 to 1.2 T, mainly used to recover iron-containing minerals such as hematite with weak magnetic separation.

[0029] Further preferred, the high-intensity magnetic separation operation adopts the ZH type flat ring high-intensity magnetic separator, which has the advantages of high separation accuracy and high product recovery rate.

[0030] Preferably, during the flotation-weak magnetic-strong magnetic process or the weak magnetic-strong magnetic process, water is continuously circulated within it; when the potassium content in the water is enriched to more than 60 g / L, it can be used as a raw material for potassium extraction. After being processed by a mature potassium chloride crystallization process, a potassium chloride product with a content of ≥90% is finally obtained.

[0031] Preferably, zinc-containing products obtained through flotation-weak magnetic-strong magnetic processes or weak magnetic-strong magnetic processes are used as raw materials for further zinc extraction. They are then smelted using mature metallurgical methods such as rotary kiln methods to obtain zinc oxide products. The resulting kiln slag can be used as a building material raw material.

[0032] The method of this invention demonstrates better adaptability to iron-containing dust and sludge from different sources, with different properties, and different compositions. In actual production processes and equipment configurations, to improve adaptability to various types of iron-containing dust and sludge, a general process configuration based on flotation-weak magnetic flux-strong magnetic flux can be adopted. Simultaneously, the process is designed to be flexible and adaptable, such as… Figure 1 As shown, Figure 1 This can also serve as a process flow diagram for a specific embodiment. In actual production, depending on the source, properties, and composition of the iron-containing dust and sludge, the process can be switched between "flotation-weak magnetic-strong magnetic" and "weak magnetic-strong magnetic" processes. For example, when the raw material is blast furnace dust, the "flotation-weak magnetic-strong magnetic" process is preferred; when the raw material is one or more types of head ash or cyclone ash, the "weak magnetic-strong magnetic" process is preferred. When directly configuring the general process according to the flotation-weak magnetic-strong magnetic process without switching processes, adjusting the dosage of collectors and frothers based on the actual processing conditions can effectively adapt to changes in raw materials and achieve stable and efficient mineral processing. For example, when the raw material is blast furnace dust, the collector and frother can be adjusted according to the aforementioned flotation-weak magnetic-strong magnetic process requirements. If the raw material is head ash or cyclone ash, it is preferable to add as little collector and frother as possible or none at all, essentially treating it directly through the weak magnetic-strong magnetic process.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] This invention targets iron-containing dust and sludge, innovatively applying mineral processing technology to the field of iron and steel metallurgy. It proposes a closed-loop process system that can achieve the separation of iron, carbon, zinc, and potassium in iron-containing dust and sludge in a single process, with no waste residue or wastewater discharge, making it an environmentally friendly process. In terms of process technology, efficient flotation and weak-magnetic-strong magnetic separation technologies are combined with mature potassium chloride crystallization and zinc extraction technologies, enabling efficient recovery and utilization of all components of the iron-containing dust and sludge. Advanced equipment and process combinations, effective energy-saving measures, and controlled operating costs result in low product consumption and good economic benefits. The process route of this invention is simple, concise, efficient, and reasonable, adaptable to the treatment of various types of iron-containing dust and sludge, and has strong overall adaptability. The transformation of iron-containing dust and sludge from solid waste to resource utilization truly realizes a circular economy in the steelmaking process, yielding not only good economic benefits but also significant social benefits. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a process flow diagram of the comprehensive utilization of iron-containing dust and sludge resources in this invention. Detailed Implementation

[0037] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0038] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0039] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0040] Example 1:

[0041] A method for the efficient and comprehensive utilization of iron-containing dust and sludge includes the following steps:

[0042] 1) An iron-containing dust sludge (blast furnace dust), wherein the C, Fe, and Zn contents in the raw material are 19.30%, 35.85%, and 4.77%, respectively. After stirring and pulping, the raw material is prepared into a slurry with a mass concentration of 20% to 30%. 5.35% of the raw material is dissolved in the slurry. The distribution rates of C, Fe, and Zn dissolved in water in the raw material reach 1.57%, 0.07%, and 5.55%, respectively.

[0043] The above slurry is screened to separate the residue, resulting in undersize slurry with a mass concentration of 15% to 20%. The screen used for separating the residue is a high-frequency fine screen with a screen aperture size of 0.3 mm.

[0044] 2) The undersize slurry enters the flotation-weak magnetic-strong magnetic process. The specific steps are as follows: First, diesel oil is added as a collector, and MIBC is added as a frother. The flotation froth (foam product) obtained after three roughing flotation operations is combined to form a carbon rough concentrate. The total diesel oil usage for the three roughing flotation operations is 875 g / t, the total MIBC usage is 175 g / t, and the flotation aeration rate is 0.34 m³ / t. 3 .m - 2 .min -1 .

[0045] 3) After one blank cleaning flotation operation, carbon concentrate product was obtained from the rough carbon concentrate. The carbon concentrate product yield was 8.77%, the carbon grade was 56.65%, the iron grade was 12.52%, and the zinc grade was 4.81%. The carbon, iron, and zinc recovery rates were 25.73%, 3.06%, and 8.84%, respectively.

[0046] 4) The in-tank products obtained after three roughing flotation operations are then subjected to one weak magnetic separation and one strong magnetic separation, respectively. The resulting weak and strong magnetic concentrates are combined to form the iron concentrate product. The weak magnetic separation operation uses a Φ400×300 electromagnetic weak magnetic separator with a magnetic field strength of 159.24 kA / m, and the strong magnetic separation operation uses a ZH560 flat ring strong magnetic separator with a magnetic induction intensity of 1.1T. The iron concentrate yield is 48.94%, with a carbon grade of 5.80%, an iron grade of 51.66%, and a zinc grade of 3.14%. The carbon, iron, and zinc recoveries are 15.74%, 70.13%, and 35.03%, respectively.

[0047] 5) The product obtained from the primary cleaning of the carbon rough concentrate and the tailings from the primary high-intensity magnetic separation are combined to form a zinc-containing product. The zinc-containing product yield is 36.94%, with a carbon content of 29.76%, an iron content of 25.95%, and a zinc content of 6.53%. The carbon, iron, and zinc recovery rates are 56.96%, 26.74%, and 50.58%, respectively.

[0048] Example 2:

[0049] A method for the efficient and comprehensive utilization of iron-containing dust and sludge includes the following steps:

[0050] 1) An iron-containing dust (machine head ash), the raw material contains 2.11% C, 21.21% Fe and 0.16% Zn, respectively. After stirring and pulping, it is prepared into a slurry with a mass concentration of 20% to 30%. 55.59% of the raw material is dissolved in the slurry. The distribution rates of C, Fe and Zn soluble in water in the raw material reach 3.58%, 0.38% and 21.78%, respectively.

[0051] The above slurry is subjected to screening and slag separation treatment to obtain undersize slurry with a mass concentration of 20% to 25%. The screening and slag separation treatment is performed using a high-frequency fine screen with a screen aperture size of 0.3 mm.

[0052] 2) The undersize slurry undergoes a weak magnetic separation followed by a strong magnetic separation. The specific steps are as follows: first, a weak magnetic separation is performed, followed by a strong magnetic separation. The resulting weak and strong magnetic concentrates are then combined to form the iron concentrate product. The weak magnetic separation uses a Φ400×300 electromagnetic weak magnetic separator with a magnetic field strength of 159.24 kA / m. The strong magnetic separation uses a ZH560 flat-ring strong magnetic separator with a magnetic induction intensity of 1.1 T. The iron concentrate yield is 37.82%, with a carbon grade of 3.18%, an iron grade of 52.05%, and a zinc grade of 0.23%. The carbon, iron, and zinc recoveries are 57.05%, 92.82%, and 53.93%, respectively.

[0053] 3) The tailings obtained after one strong magnetic separation become the final tailings product. The tailings product yield is 6.59%, with a carbon content of 12.61%, an iron content of 21.92%, and a zinc content of 0.59%. The carbon, iron, and zinc recovery rates are 39.37%, 6.80%, and 24.29%, respectively. The magnetic separation tailings can be further used as raw materials for making building materials.

[0054] Example 3:

[0055] A method for the efficient and comprehensive utilization of iron-containing dust and sludge includes the following steps:

[0056] 1) An iron-containing dust sludge (cyclone ash), the raw material contains 28.59% C, 36.59% Fe and 0.23% Zn, respectively, and is mixed and prepared into a slurry with a mass concentration of 20% to 30%. The C, Fe and Zn in the raw material are almost insoluble in water;

[0057] The above slurry is subjected to screening and slag separation treatment to obtain undersize slurry with a mass concentration of 20% to 25%. The screening and slag separation treatment is performed using a high-frequency fine screen with a screen aperture size of 0.3 mm.

[0058] 2) The undersize slurry undergoes a weak magnetic separation followed by a strong magnetic separation. The resulting weak and strong magnetic concentrates are then combined to form the iron concentrate product. The weak magnetic separation uses a Φ400×300 electromagnetic separator with a magnetic field strength of 159.24 kA / m, while the strong magnetic separation uses a ZH560 strong magnetic separator with a magnetic induction intensity of 0.8 T. The iron concentrate yield is 65.93%, containing 51.16% iron, 9.84% carbon, and 0.31% zinc. The recovery rates for iron, carbon, and zinc are 92.19%, 22.69%, and 87.59%, respectively.

[0059] 3) The tailings obtained after one strong magnetic separation can be used as carbon concentrate. The carbon concentrate yield is 34.07%, with a carbon content of 64.87%, an iron content of 8.39%, and a zinc content of 0.084%. The recovery rates of carbon, iron, and zinc are 77.31%, 7.81%, and 12.41%, respectively.

[0060] Example 4:

[0061] A method for the efficient and comprehensive utilization of iron-containing dust and sludge includes the following steps:

[0062] 1) An iron-containing dust sludge (blast furnace dust), the raw materials contain 26.99% C, 29.71% Fe and 6.23% Zn, respectively, and are mixed and prepared into a slurry with a mass concentration of 20% to 30%. The C, Fe and Zn in the raw materials are almost insoluble in water;

[0063] The above slurry is subjected to screening and slag separation treatment to obtain undersize slurry with a mass concentration of 20% to 25%. The screening and slag separation treatment is performed using a high-frequency fine screen with a screen aperture size of 0.3 mm.

[0064] 2) The undersize slurry undergoes a flotation-weak magnetic-strong magnetic process. The specific steps are as follows: the undersize slurry is subjected to one roughing stage and two scavenging stages sequentially; the roughing and scavenging froth products obtained from the one roughing and two scavenging stages are combined to form the carbon concentrate product; diesel fuel is added as a collector, and MIBC (Mild Chemical Carbonate) is added as a frother. The total diesel fuel consumption for the three flotation operations (one roughing stage and two scavenging stages) is 875 g / t, and the total MIBC consumption is 175 g / t. The flotation aeration rate is 0.34 m³ / t. 3 .m -2 .min -1 .

[0065] 3) The carbon rough concentrate is subjected to two flotation blank cleaning operations to obtain the carbon concentrate product.

[0066] 4) The products obtained from the flotation cells after one roughing operation and two scavenging operations are then subjected to one weak magnetic separation and one strong magnetic separation, respectively, to combine the weak magnetic concentrate and the strong magnetic concentrate into iron concentrate. The weak magnetic separation operation uses a Φ400×300 electromagnetic weak magnetic separator with a magnetic field strength of 159.24 kA / m, and the strong magnetic separation operation uses a ZH560 flat-ring strong magnetic separator with a magnetic induction intensity of 1.2T. The iron concentrate yield is 44.37%, with a carbon grade of 1.19%, an iron grade of 53.46%, and a zinc grade of 3.12%. The carbon, iron, and zinc recoveries are 1.97%, 79.83%, and 22.20%, respectively.

[0067] 5) The middlings (product from the flotation cell) obtained from two blank cleaning processes of the carbon rough concentrate and the tailings from the high-intensity magnetic separation are combined to form a zinc-containing product. The zinc-containing product yield is 28.40%, with a carbon content of 29.21%, an iron content of 15.74%, and a zinc content of 13.22%. The carbon, iron, and zinc recoveries are 30.74%, 15.04%, and 60.23%, respectively.

[0068] Example 5:

[0069] A method for the efficient and comprehensive utilization of iron-containing dust and sludge includes the following steps:

[0070] 1) An iron-containing dust sludge (blast furnace dust), the raw material contains 16.77% C, 45.59% Fe and 1.43% Zn, respectively, and is mixed and prepared into a slurry with a mass concentration of 20% to 30%. The C, Fe and Zn in the raw material are almost insoluble in water;

[0071] The above slurry is subjected to screening and slag separation treatment to obtain undersize slurry with a mass concentration of 20% to 25%. The screening and slag separation treatment is performed using a high-frequency fine screen with a screen aperture size of 0.3 mm.

[0072] 2) The undersize slurry undergoes a weak magnetic separation followed by a strong magnetic separation. The specific steps are as follows: first, a weak magnetic separation is performed, followed by a strong magnetic separation. The weak and strong magnetic concentrates are then combined to form the iron concentrate product. The weak magnetic separation uses a Φ400×300 electromagnetic weak magnetic separator with a magnetic field strength of 159.24 kA / m. The strong magnetic separation uses a ZH560 flat-ring strong magnetic separator with a magnetic induction intensity of 0.8 T. The iron concentrate yield is 80.19%, containing 52.58% iron, 8.03% carbon, and 1.23% zinc. The recovery rates for iron, carbon, and zinc are 92.49%, 38.37%, and 68.97%, respectively.

[0073] 3) The tailings obtained after one strong magnetic separation can be used as carbon concentrate. The carbon concentrate yield is 19.81%, with a carbon content of 52.17%, an iron content of 17.29%, and a zinc content of 2.24%. The recovery rates of carbon, iron, and zinc are 61.63%, 7.51%, and 31.03%, respectively.

[0074] In the flotation-weak magnetic-strong magnetic process or weak magnetic-strong magnetic process described in the above embodiments, water continuously circulates. When the potassium content in the water is enriched to 60 g / L or higher, it can be used as a raw material for potassium extraction. After processing with a mature potassium chloride crystallization process, a potassium chloride product with a content of ≥90% is finally obtained. Furthermore, the zinc-containing product obtained from the flotation-weak magnetic-strong magnetic process or weak magnetic-strong magnetic process can be used as a raw material for further zinc extraction. It can be smelted using mature metallurgical methods such as the rotary kiln method to obtain zinc oxide. The resulting kiln slag can be used as a building material raw material.

Claims

1. A method for the efficient and comprehensive utilization of iron-containing dust and sludge, characterized in that, Includes the following steps: (1) The iron-containing dust and mud are stirred and pulped, and screened to separate the slag, so as to obtain the slurry under the screen; (2) The undersize slurry is subjected to flotation-weak magnetic-strong magnetic process or weak magnetic-strong magnetic process; The flotation-weak magnetic field-strong magnetic field process includes the following steps: ① The undersize slurry obtained from step (1) is subjected to 1 to 3 roughing flotation operations, and the froth products obtained from the roughing flotation operations are combined into carbon crude concentrate products; ②The carbon crude concentrate product obtained in step ① is subjected to 1 to 3 more fine flotation operations to obtain the final fine froth product, which is the carbon concentrate product. ③ The products obtained from the roughing flotation operations in step ① are subjected to 1-2 weak magnetic separations and 1-2 strong magnetic separations respectively. The weak magnetic concentrate and strong magnetic concentrate are then combined to form iron concentrate products. ④ Combine the strong magnetic separation tailings obtained in step ③ and the in-tank product obtained in step ② into a zinc-containing product; The weak magnetic field-strong magnetic field process includes the following steps: ① The undersize slurry obtained from step (1) is subjected to 1-2 weak magnetic separations and 1-2 strong magnetic separations. The resulting weak magnetic concentrate and strong magnetic concentrate are combined to form an iron concentrate product. ② For the strong magnetic separation tailings obtained in step ①, when the carbon content of the strong magnetic separation tailings is >55%, the strong magnetic separation tailings are directly used as carbon concentrate products without flotation processing; when the carbon content of the strong magnetic separation tailings is >15% and ≤55%, the strong magnetic separation tailings are processed using the flotation-weak magnetic-strong magnetic process; when the carbon content of the strong magnetic separation tailings is ≤15%, the strong magnetic separation tailings are used as raw materials for making building materials. During the flotation-weak magnetic-strong magnetic process or the weak magnetic-strong magnetic process, water is continuously circulated. When the potassium content in the water is enriched to more than 60 g / L, it is used as raw material for potassium extraction. After being processed by the potassium chloride crystallization process, a potassium chloride product with a content of ≥90% is finally obtained. For zinc-containing products obtained through flotation-weak magnetic-strong magnetic processes or weak magnetic-strong magnetic processes, they are used as raw materials for zinc extraction. They are then smelted using metallurgical methods to obtain zinc oxide products, and the resulting kiln slag is used as a building material raw material.

2. The method according to claim 1, characterized in that, The iron-containing dust and sludge is one or more of blast furnace dust, machine head dust, and cyclone dust; the blast furnace dust has a carbon content of <30%, an iron content of <50%, and a zinc content of <8%; the machine head dust has a carbon content of <5%, an iron content of <30%, and a zinc content of <1%; and the cyclone dust has a carbon content of <30%, an iron content of <50%, and a zinc content of <1%.

3. The method according to claim 2, characterized in that, When the iron-containing dust is blast furnace dust, the undersize slurry is subjected to flotation-weak magnetic-strong magnetic processes; when the iron-containing dust is one or more of machine head ash and cyclone ash, the undersize slurry is subjected to weak magnetic-strong magnetic processes.

4. The method according to claim 1, characterized in that, The stirring and pulping, screening and slag separation process includes the following steps: the pulping process involves stirring and preparing iron-containing dust and sludge into a slurry with a mass concentration of 20-30%; the screening and slag separation process uses a high-frequency fine screen or a linear vibrating screen with a screen aperture size of 0.3-0.6mm, and the screening and slag separation process yields undersize slurry with a mass concentration of 15-25%.

5. The method according to claim 1, characterized in that, In steps ① and ② of the flotation process (flotation-weak magnetic-strong magnetic flotation), the flotation equipment used is a flotation machine or flotation column. In the first to third roughing flotation operations of step ①, the flotation collector used is at least one of diesel oil and kerosene, the frother used is MIBC, the total amount of flotation collector added is 500-1000 g / t of raw material, the ratio of flotation collector to frother added is 2.5:1-5:1, and the flotation aeration rate is 0.2-0.4 m³ / t. 3 .m -2 .min -1 .

6. The method according to claim 1 or 5, characterized in that, The iron concentrate product has an iron content greater than 50%, and the carbon concentrate product has a carbon content greater than 55%.

7. The method according to claim 1 or 5, characterized in that, In the flotation-weak magnetic-strong magnetic process or the weak magnetic-strong magnetic process, the weak magnetic separation operation adopts an electromagnetic or permanent magnet weak magnetic separator, and the strong magnetic separation operation adopts a ZH-type flat ring strong magnetic separator or a Slon vertical ring strong magnetic separator. The strong magnetic separation is carried out under a magnetic induction intensity of 0.6~1.2T.

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